Reporting from Washington - As President Obama struggles over a new military strategy for Afghanistan, his advisors are trying to satisfy sharply divergent demands: assuring Americans that any military buildup will be limited while convincing Pakistan and other wary allies that the U.S. presence is substantial and not about to end.

The difficulty in determining a strategy that can mollify both these conflicting constituencies helps to explain why the administration's months-long search for a new approach to Afghanistan remains unresolved.

On the domestic front, Obama risks alienating a political base that has become increasingly impatient with the 8-year-old war.

At the same time, the president faces potentially serious setbacks in Afghanistan and Pakistan if the heads of those governments -- not to mention the leaders of the Taliban insurgency -- see any indication of a wavering U.S. commitment. "This is precisely what muddles their strategic discussion," said Juan Zarate, who served as deputy national security advisor in the George W. Bush administration. "They have to thread a needle here. [Obama] can't be seen domestically to be articulating a 20-year commitment to Afghanistan, while at the same time, he can't be signaling a quick exit to our allies and enemies on the ground and in the region."

Pakistan is key to the debate because of concerns that its powerful intelligence service would ramp up support for Afghan Taliban militants as part of a hedge strategy aimed at preserving Pakistani influence next door in the event of a U.S. exit from the region.

Any indication of a U.S. pullback would embolden Taliban leaders who have gained control of large swaths of territory through a campaign of intimidation that has convinced many locals that the Islamic insurgents will be around long after U.S. forces have left.

Obama could seek to manage the countervailing pressures in several ways, current and former U.S. official say.

One would be to announce a broader commitment to the "soft power" aspects of the mission: building schools and health clinics and improving public services. Such steps are likely to be welcomed by both regional allies and many antiwar critics at home.

Another option would be to emphasize the threat from the militants, an argument that still has resonance in the United States. Polls show that even some Americans who have misgivings about the troop deployments fear the consequences of withdrawal.

White House officials have said that Obama may still be weeks away from reaching his decision on whether to grant the request of Army Gen. Stanley A. McChrystal, the top commander of U.S. and NATO forces in Afghanistan, for a reported 40,000 additional American troops. Republicans have demanded that Obama agree to McChrystal's request, but many Democrats are wary of a major increase in forces.

The competing imperatives within the administration have been on display in a series of recent public exchanges.

During her trip to Pakistan last week, Secretary of State Hillary Rodham Clinton was asked by a Pakistani journalist when administration officials would "make up your minds about what to do in Afghanistan." The journalist noted that a decision not to send additional troops would "be seen as defeat in this country."

Clinton replied, "The president is well aware that it's important that he show resolve, that he show a commitment to seeing this effort through."

But one of Obama's top domestic policy advisors, Valerie Jarrett, appeared to send a different signal Sunday when she said in a television interview that the United States would work with Afghan President Hamid Karzai to improve conditions in his country "as we try to bring this war to a close."

Obama is crafting his new policy at a time of declining public support and growing confusion among Americans about the Afghanistan war. Public support for maintaining troops in Afghanistan fell to 50% in September, compared with 57% in June, according to Pew Research Center polling.

The ranks of powerful critics of the war have swelled in Congress in recent months, and now include House Speaker Nancy Pelosi (D-San Francisco), House Appropriations Committee Chairman David R. Obey (D-Wis.) and Rep. John P. Murtha (D-Pa.), an influential voice on military matters.

But the political challenge for Obama goes beyond protecting his Democratic base. A more looming threat may be attacks by Republicans during next year's midterm election campaign if the president spurns McChrystal's request for additional troops.

Sen. Lindsey Graham (R-S.C.) said Obama would win support of most congressional Republicans if he approved McChrystal's request. But, he acknowledged, "a new strategy that requires 40,000 more troops is not what most Americans want to hear right now."

In Afghanistan and Pakistan, the opposite is true.

Karzai's government has been deeply concerned that anything short of a full-scale U.S. commitment would further undermine its tenuous hold on provinces not already in Taliban control.

In an unusual step, Said T. Jawad, the Afghan ambassador in Washington, has traveled around the U.S. to argue that the Obama administration should add at least 40,000 troops. During an appearance in Arkansas last month, he said that failing to do so would "put the lives of American and NATO troops in danger."

Pakistan has posed a greater national security concern for the U.S. since Al Qaeda's leadership relocated to the country's tribal belt along the Afghan border after being driven from Afghanistan in 2001. Pakistan also has been a vital counter-terrorism partner, cooperating with the CIA on drone strikes against Al Qaeda and Taliban targets and launching major military offensives over the last year against insurgent strongholds.

U.S. officials and experts downplayed the risk of losing such cooperation from Pakistan, noting that the government in Islamabad sees the operations as essential to combating the country's internal insurgent threat.

But U.S. intelligence officials repeatedly have charged that elements of the Pakistani intelligence and security services undermine U.S. goals by supporting militant groups accused of orchestrating attacks in Afghanistan. Some fear that such ties would strengthen if the U.S. is seen as wavering.

Leaders in Islamabad already view U.S. intentions with distrust because of their experience in the 1980s, when the U.S. departed after using Pakistan as its base to supply anti-Soviet fighters in Afghanistan.

Pakistani officials are "always looking for the same thing -- is the United States going to leave suddenly and leave a mess behind?" said Shuja Nawaz, a regional analyst and former Pakistani government official. If Pakistan fears it will happen again, he said, "it may start affecting some of their hedging strategies."

The Afghan Taliban also appears to be tracking the administration's deliberations, which have centered on the question of whether the U.S. should remain committed to building a functioning Afghan government or should focus more narrowly on targeting militants.

Last week, Mullah Brader Akhund, a senior Afghan Taliban figure, released a statement that seemed designed to sway that debate, warning Obama "to avoid wasting your time on ways which are not pragmatic" and to "put an end to the game of colonialization."

North Atlantic Treaty Organization allies are watching U.S. steps, with an eye toward the exits. "If they think we're shaky, and we're on the way out, they're going to be out the door faster," said William S. Cohen, secretary of Defense in the Clinton administration.